/* knownports design system (mockup). Geist Sans + Geist Mono, self-hosted. */
@font-face{font-family:"Geist";src:url(/assets/fonts/geist-sans-latin-400-normal.woff2) format("woff2");font-weight:400;font-display:swap}
@font-face{font-family:"Geist";src:url(/assets/fonts/geist-sans-latin-500-normal.woff2) format("woff2");font-weight:500;font-display:swap}
@font-face{font-family:"Geist";src:url(/assets/fonts/geist-sans-latin-600-normal.woff2) format("woff2");font-weight:600;font-display:swap}
@font-face{font-family:"Geist";src:url(/assets/fonts/geist-sans-latin-700-normal.woff2) format("woff2");font-weight:700;font-display:swap}
@font-face{font-family:"Geist Mono";src:url(/assets/fonts/geist-mono-latin-400-normal.woff2) format("woff2");font-weight:400;font-display:swap}
@font-face{font-family:"Geist Mono";src:url(/assets/fonts/geist-mono-latin-500-normal.woff2) format("woff2");font-weight:500;font-display:swap}

:root{
  --bg:#F7F6F2; --paper:#FFFFFF; --ink:#15171C; --ink2:#464B56; --ink3:#626773;
  --rule:#DCD9CF; --rule2:#ECEAE3;
  --brand:#2D3FCF; --brand-ink:#1E2B9E; --tint:#E8EAFB;
  --tcp:#2D3FCF; --udp:#C9690F; --sctp:#0E8174; --dccp:#9C3487;
  --free:#E9E7DF;
  --sans:"Geist",system-ui,-apple-system,"Segoe UI",sans-serif;
  --mono:"Geist Mono",ui-monospace,"SFMono-Regular",Consolas,monospace;
  --wrap:1088px; --text:688px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:400 17px/1.6 var(--sans);font-variant-numeric:tabular-nums}
a{color:var(--brand);text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:3px;text-decoration-color:rgba(45,63,207,.35)}
a:hover{text-decoration-color:currentColor}
:focus-visible{outline:3px solid var(--brand);outline-offset:2px;border-radius:2px}
code,.nm{font-family:var(--mono);font-size:max(14px,.9em);font-weight:500;color:var(--ink);letter-spacing:-.01em}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 24px}
.text{max-width:var(--text)}
.vh{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* top bar: one line, no box */
.top{display:flex;align-items:center;gap:32px;padding:20px 0 0}
.top .logo{display:block;line-height:0}
.top nav{display:flex;gap:24px;margin-left:auto;font-size:15px;font-weight:500}
.top nav a{color:var(--ink2);text-decoration:none}
.top nav a[aria-current]{color:var(--ink);box-shadow:inset 0 -2px 0 var(--brand)}
.crumb{font-size:14px;color:var(--ink3);margin:40px 0 8px}
.crumb a{color:var(--ink3)}

h1,h2,h3{font-weight:600;letter-spacing:-.02em;line-height:1.15;margin:0}
h2{font-size:28px;margin:0 0 16px}
h3{font-size:20px;margin:0 0 8px;letter-spacing:-.01em}
p{margin:0 0 16px}

/* ---------- port page head ---------- */
.porthead{display:grid;grid-template-columns:auto 1fr;gap:8px 40px;align-items:end;margin:0 0 24px}
.porthead h1{font-size:120px;line-height:.86;letter-spacing:-.055em;font-weight:600}
.porthead h1 small{display:block;font-size:20px;letter-spacing:0;font-weight:500;color:var(--ink3);line-height:1;margin:0 0 12px}
.porthead h1 .amp{color:var(--ink3);font-weight:400}
.names{padding-bottom:6px}
.names ul{list-style:none;margin:0;padding:0}
.names li{display:flex;flex-wrap:wrap;gap:4px 12px;align-items:baseline;padding:4px 0}
.names li code{font-size:22px}
.names .lbl{color:var(--ink2);font-size:16px}
.names .pr{font-size:14px;color:var(--ink3);white-space:nowrap}
.lede{font-size:20px;line-height:1.55;max-width:760px;margin:0 0 32px;color:var(--ink)}
.lede code{font-size:.85em}

/* protocol keys: square swatch + word, no pills */
.k{display:inline-flex;align-items:center;gap:6px;font-size:14px;font-weight:500;color:var(--ink2)}
.k i{width:10px;height:10px;border-radius:2px;display:inline-block}
.k.tcp i{background:var(--tcp)}.k.udp i{background:var(--udp)}.k.sctp i{background:var(--sctp)}.k.dccp i{background:var(--dccp)}
.k.res i{background:repeating-linear-gradient(135deg,var(--ink3) 0 1.5px,transparent 1.5px 4px);box-shadow:inset 0 0 0 1px var(--ink3)}
.k.free i{background:var(--free)}

/* figure */
figure{margin:0 0 48px}
.fig{background:var(--paper);border-radius:12px;padding:24px 24px 16px}
figcaption{font-size:14px;color:var(--ink3);margin-top:12px;display:flex;flex-wrap:wrap;gap:8px 20px;align-items:center}
figcaption .cap{flex-basis:100%;color:var(--ink2)}
svg{display:block;max-width:100%;height:auto}
svg text{font-family:var(--sans)}
.only-wide{display:block}.only-narrow{display:none}

/* sections: weight by rhythm, not boxes */
.sec{margin:0 0 56px}
.sec.minor{margin-bottom:40px}
.sec h2 + .sub{margin-top:-8px;color:var(--ink3);font-size:15px}
.cols{display:grid;grid-template-columns:1fr 1fr;gap:40px}
.facts{margin:0;padding:0;list-style:none}
.facts li{padding:12px 0;border-top:1px solid var(--rule2)}
.facts li:last-child{border-bottom:1px solid var(--rule2)}

/* tables */
.tbl{width:100%;border-collapse:collapse;font-size:16px;background:transparent}
.tbl th{font-size:14px;font-weight:500;color:var(--ink3);text-align:left;padding:8px 12px 8px 0;border-bottom:1px solid var(--rule);white-space:nowrap}
.tbl td{padding:12px 12px 12px 0;border-bottom:1px solid var(--rule2);vertical-align:top}
.tbl td.n{font-weight:600;white-space:nowrap}
.tbl td.d{white-space:nowrap;color:var(--ink2)}
.tbl td .lbl2{color:var(--ink2)}
.tbl tr:target td{background:var(--tint)}
.tbl .pk{display:flex;flex-wrap:nowrap;gap:4px 10px}
.tbl tr.prof td.n a{font-weight:700}
.dash{color:var(--ink3)}
.tbl.big td{padding:10px 12px 10px 0}
.tbl .gaprow td{color:var(--ink3);font-size:14px;padding:6px 0;border-bottom:1px solid var(--rule2);background:repeating-linear-gradient(90deg,transparent 0 6px,rgba(0,0,0,.02) 6px 12px)}

/* link line "look up another port": inline, not boxed */
.inline-form{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center;padding:24px 0;border-top:1px solid var(--rule)}
.inline-form label{font-weight:500}
.inline-form input{font:500 17px var(--mono);width:200px;padding:10px 12px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.btn{font:600 16px var(--sans);background:var(--brand);color:#fff;border:0;border-radius:8px;padding:11px 18px;cursor:pointer;text-decoration:none;display:inline-block}
.btn:hover{background:var(--brand-ink)}

/* ---------- home / tool ---------- */
.hero{padding:72px 0 24px}
.hero h1{font-size:56px;letter-spacing:-.04em;max-width:900px;margin:0 0 16px}
.hero .deck{font-size:20px;color:var(--ink2);max-width:680px;margin:0 0 32px}
.q{display:grid;grid-template-columns:1fr auto;gap:0;background:var(--paper);border-radius:14px;box-shadow:0 1px 0 var(--rule),0 0 0 1px var(--rule);max-width:880px}
.q:focus-within{box-shadow:0 0 0 2px var(--brand)}
.q label.vh+input,.q input{font:500 28px var(--mono);letter-spacing:-.02em;border:0;background:transparent;padding:20px 24px;min-width:0;color:var(--ink);outline:0}
.q .btn{margin:8px;font-size:17px;padding:0 24px;border-radius:10px}
.opts{display:flex;flex-wrap:wrap;gap:12px 24px;align-items:center;margin:16px 0 0;font-size:15px;color:var(--ink2)}
.opts select{font:500 15px var(--sans);padding:6px 8px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink)}
.opts .eg a{font-family:var(--mono);font-size:15px;margin-right:8px}
.result{margin:40px 0 0;max-width:var(--wrap)}
.res-head{display:flex;flex-wrap:wrap;align-items:baseline;gap:8px 24px;margin:0 0 16px}
.res-head .big{font-size:64px;font-weight:600;letter-spacing:-.05em;line-height:1}
.res-head .what{font-size:18px;color:var(--ink2)}
.res-meta{display:flex;flex-wrap:wrap;gap:8px 32px;font-size:15px;color:var(--ink2);margin:16px 0 0}
.res-meta b{font-weight:600;color:var(--ink)}
.note{font-size:14px;color:var(--ink3);margin:16px 0 0;max-width:720px}
.sumline{font-size:18px;margin:0 0 16px}
.sumline b{font-weight:600}

/* band: full-bleed white section */
.band{background:var(--paper);padding:64px 0;margin:64px 0}
.band h2{font-size:32px}
.band .deck{color:var(--ink2);font-size:18px;max-width:720px;margin:0 0 32px}

/* range index on home: a ruled list with a bar per hub */
.rlist{list-style:none;margin:0;padding:0;columns:2;column-gap:48px}
.rlist li{break-inside:avoid;display:grid;grid-template-columns:128px 1fr 56px;gap:12px;align-items:center;padding:8px 0;border-bottom:1px solid var(--rule2);font-size:15px}
.rlist .bar{height:8px;background:var(--free);border-radius:4px;overflow:hidden}
.rlist .bar i{display:block;height:100%;background:var(--tcp);border-radius:4px}
.rlist .v{text-align:right;color:var(--ink2)}
.idx{display:grid;grid-template-columns:repeat(4,1fr);gap:0 32px;margin:0;padding:0;list-style:none}
.idx li{padding:10px 0;border-bottom:1px solid var(--rule2);display:flex;gap:12px;align-items:baseline}
.idx b{font-weight:600;min-width:56px}
.idx a{text-decoration:none;color:var(--ink)}
.idx a:hover code{color:var(--brand)}
.glist{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,1fr);gap:0 48px}
.glist li{padding:20px 0;border-top:1px solid var(--rule)}
.glist a{font-size:20px;font-weight:600;letter-spacing:-.01em;text-decoration:none;color:var(--ink)}
.glist a:hover{color:var(--brand)}
.glist p{margin:6px 0 0;color:var(--ink2);font-size:16px}

/* hub */
.hubhead h1{font-size:64px;letter-spacing:-.045em;margin:0 0 16px}
.hubhead h1 small{display:block;font-size:20px;font-weight:500;color:var(--ink3);letter-spacing:0;margin:0 0 8px}
.hubfacts{font-size:19px;max-width:780px;margin:0 0 32px}
.jump{display:flex;flex-wrap:wrap;gap:8px 16px;font-size:15px;margin:0 0 16px;color:var(--ink3)}
.jump a{font-family:var(--mono);font-size:14px}

/* article */
.art{max-width:var(--text)}
.art h1{font-size:48px;letter-spacing:-.035em;margin:0 0 20px}
.art .by{font-size:15px;color:var(--ink3);margin:0 0 40px;display:flex;flex-wrap:wrap;gap:4px 16px}
.art .by b{color:var(--ink);font-weight:600}
.art p,.art li{font-size:18px;line-height:1.7}
.art p.first{font-size:21px;line-height:1.55}
.art h2{font-size:26px;margin:48px 0 16px}
.art .wide{margin:32px 0 40px}
.art .src{font-size:15px;color:var(--ink2);border-top:1px solid var(--rule);padding-top:16px;margin-top:48px}
.art .src p{font-size:15px}

/* text pages */
.legal{max-width:var(--text);padding-bottom:40px}
.legal h1{font-size:44px;letter-spacing:-.03em;margin:40px 0 24px}
.legal h2{font-size:22px;margin:40px 0 12px}
.legal p,.legal li{font-size:17px}
.legal .upd{font-size:15px;color:var(--ink3)}

/* footer: light, two rows */
.foot{border-top:1px solid var(--rule);margin-top:80px;padding:32px 0 48px;font-size:14px;color:var(--ink3)}
.foot .row{display:flex;flex-wrap:wrap;gap:8px 24px;align-items:center;justify-content:space-between}
.foot nav{display:flex;flex-wrap:wrap;gap:8px 20px}
.foot nav a{color:var(--ink2)}
.foot p{margin:16px 0 0;max-width:760px}

/* ---------- mobile ---------- */
@media (max-width:760px){
  body{font-size:16px}
  .wrap{padding:0 16px}
  .top{gap:12px;flex-wrap:wrap;padding-top:16px}
  .top nav{gap:16px;margin-left:0;width:100%;font-size:15px}
  .crumb{margin-top:24px}
  .porthead{grid-template-columns:1fr;gap:16px}
  .porthead h1{font-size:88px}
  .names li code{font-size:19px}
  .lede{font-size:18px}
  .fig{padding:16px 12px 12px;border-radius:10px}
  .only-wide{display:none}.only-narrow{display:block}
  .cols{grid-template-columns:1fr;gap:0}
  .hero{padding:32px 0 8px}
  .hero h1{font-size:34px}
  .hero .deck{font-size:17px;margin-bottom:24px}
  .q input{font-size:20px;padding:16px}
  .q .btn{padding:0 16px;margin:6px}
  .res-head .big{font-size:48px}
  .band{padding:40px 0;margin:48px 0}
  .band h2{font-size:26px}
  .rlist{columns:1}
  .idx{grid-template-columns:repeat(2,minmax(0,1fr));gap:0 16px}
  .idx li{flex-wrap:wrap;gap:0 8px}.idx b{min-width:0}.idx code{overflow-wrap:anywhere}
  .glist{grid-template-columns:1fr}
  .hubhead h1{font-size:40px}
  .hubfacts{font-size:17px}
  .art h1{font-size:34px}
  .art p,.art li{font-size:17px}
  .art p.first{font-size:19px}
  .legal h1{font-size:34px}
  h2{font-size:24px}
  /* card tables: every value carries its label */
  .tbl.rf thead{display:none}
  .tbl.rf,.tbl.rf tbody,.tbl.rf tr,.tbl.rf td{display:block;width:100%}
  .tbl.rf tr{display:grid;grid-template-columns:auto 1fr;gap:2px 12px;padding:12px 0;border-bottom:1px solid var(--rule2)}
  .tbl.rf td{border:0;padding:0;white-space:normal}
  .tbl.rf td::before{content:attr(data-l) " ";font-size:14px;font-weight:400;color:var(--ink3);margin-right:4px}
  .tbl.rf td.n{grid-row:span 3;font-size:20px;min-width:64px}
  .tbl.rf td.n::before{display:block;margin:0}
  .tbl.rf td:not(.n){grid-column:2}
  .tbl.rf .pk{display:inline-flex;flex-wrap:wrap}
  .tbl.rf .gaprow{display:block;padding:6px 0}
  .tbl.rf td.e{display:none}

}

/* header search on inner pages */
.hs{display:flex;gap:0;background:var(--paper);border-radius:8px;box-shadow:0 0 0 1px var(--rule)}
.hs:focus-within{box-shadow:0 0 0 2px var(--brand)}
.hs input{font:500 15px var(--mono);border:0;background:transparent;padding:8px 12px;width:150px;color:var(--ink);outline:0;min-width:0}
.hs button{font:600 14px var(--sans);border:0;background:transparent;color:var(--brand);padding:0 12px;cursor:pointer}
/* neighborhood strip (HTML): columns on wide screens */
.nbfig{margin:0 0 56px;background:var(--paper);border-radius:12px;padding:24px}
.nb{list-style:none;margin:0;padding:0;display:flex;justify-content:center;align-items:stretch;gap:8px}
.nb li{display:flex;flex-direction:column;align-items:center;gap:8px;min-width:0;flex:1 1 0;max-width:120px;padding:8px 4px;border-radius:8px}
.nb .cells{display:flex;flex-direction:column;gap:6px;width:100%}
.nb .cells i{display:block;height:24px;border-radius:3px;background:var(--free)}
.nb i.a.tcp{background:var(--tcp)}.nb i.a.udp{background:var(--udp)}.nb i.a.sctp{background:var(--sctp)}.nb i.a.dccp{background:var(--dccp)}
.nb i.r{background:repeating-linear-gradient(135deg,var(--ink3) 0 1.5px,#fff 1.5px 5px);box-shadow:inset 0 0 0 1.5px var(--ink3);opacity:.7}
.nb li b,.nb li>a{order:2;font-size:17px;font-weight:600;color:var(--ink);text-decoration:none}
.nb li>a:hover{color:var(--brand)}
.nb li code{order:3;font-size:14px;font-weight:400;color:var(--ink2);max-width:100%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.nb li.cur{background:var(--tint)}.nb li.cur b{color:var(--brand-ink);font-size:19px}.nb li.cur code{color:var(--ink);font-weight:500}
.nb li.lh{flex:0 0 48px;padding-left:0}.nb li.lh .cells span{height:24px;font-size:14px;font-weight:500;color:var(--ink2);display:flex;align-items:center;justify-content:flex-end}
.nb li.gap{flex:0 0 56px;justify-content:center;font-size:14px;color:var(--ink3);text-align:center;gap:0;border-left:1px dashed var(--rule);border-right:1px dashed var(--rule);border-radius:0;margin:8px 0 48px}
.nb li.gap span{font-weight:600;color:var(--ink2);font-size:15px}
.nbfig figcaption{margin-top:16px;padding-top:12px;border-top:1px solid var(--rule2)}
.nbfig .hubl{margin-left:auto;font-size:15px}
@media (max-width:760px){
  .hs{width:100%}.hs input{flex:1;width:auto;font-size:16px}
  .nbfig{padding:12px;border-radius:10px}
  .nb{flex-direction:column;gap:2px}
  .nb li{flex-direction:row;max-width:none;width:100%;gap:12px;padding:6px 8px}
  .nb li b,.nb li>a{order:0;min-width:56px}
  .nb .cells{flex-direction:row;width:auto;flex:0 0 auto}
  .nb .cells i{width:36px;height:22px}
  .nb li code{order:2}
  .nb li.lh{flex:none;padding-left:76px}.nb li.lh .cells span{width:36px;justify-content:center;height:auto;font-size:14px}
  .nb li.gap{flex:none;margin:0;border:0;border-top:1px dashed var(--rule);border-bottom:1px dashed var(--rule);justify-content:flex-start;padding-left:76px;gap:4px}
  .nbfig .hubl{margin-left:0}
}
.fam{display:flex;flex-wrap:wrap;gap:8px 24px;margin:0;font-size:16px}
.fam span{white-space:nowrap}.fam .more{white-space:normal;color:var(--ink3)}
/* build additions */
.skip:focus{position:static;width:auto;height:auto;clip:auto;padding:8px;background:var(--paper)}
.listed{font-size:15px;color:var(--ink2);margin:8px 0 0;padding:16px 0;border-top:1px solid var(--rule2)}
.listed span{color:var(--ink3);margin-right:6px}
.tbl tr.st td{color:var(--ink3);font-size:15px}
.glist.one{grid-template-columns:1fr;max-width:760px}
.hero.tool{padding-top:48px}
.cols{margin-top:48px}
.dl{margin:0}.dl dt{font-weight:600;margin-top:12px}.dl dd{margin:2px 0 0;color:var(--ink2)}
.legal.wide-legal{max-width:820px}
.legal table{margin:8px 0 24px}
.art ul li{margin:4px 0}
caption{text-align:left;font-size:14px;color:var(--ink3);padding-bottom:8px}
details.blk{border-top:1px solid var(--rule)}
details.blk summary{cursor:pointer;padding:14px 0;font-size:16px;color:var(--ink2);list-style:none;display:flex;gap:8px;align-items:baseline}
details.blk summary::-webkit-details-marker{display:none}
details.blk summary::before{content:"+";width:16px;color:var(--brand);font-weight:600}
details.blk[open] summary::before{content:"–"}
details.blk summary b{color:var(--ink);font-weight:600}
details.blk[open] summary{position:sticky;top:0;background:var(--bg);z-index:1}
.gapblk{margin:0;padding:12px 0 12px 24px;border-top:1px solid var(--rule);font-size:15px;color:var(--ink3)}
.blocks{border-bottom:1px solid var(--rule)}